GRM3 and breast cancer: Regarding mitochondrial metabolism of glutamine and glutamate, which will be depicted in the section Amino Acid Metabolism, a study showed that invasive breast cancer cells were able to secrete glutamate to induce the recycling of membrane type 1 MMP (MT1-MMP) through metabotropic glutamate receptor 3 (GRM3), thereby controlling the invasive capacity (118).